In the design of wiper blades, a multitude of criteria predetermined by lawmakers and vehicle manufacturers must be taken into account, e.g. the window region to be wiped by the wiper blades, window size, window curvature, contact pressure of the wiper blades against the window, course of air flow in front of the window, etc. For obvious reasons, this results in the fact that specific support elements for the wiper strips resting against the window are required for practically every vehicle type and even for the wiper blade on the driver""s side versus the one on the passenger side. These support elements must then be provided with the wiper blade half of a connecting device by means of which the wiper blade can be connected to the wiper arm, which is equipped with the other half of the connecting device.
In this context, the effort to comply with specifications predetermined by the vehicle manufacturer has yielded support elements that vary particularly in terms of their different lengths and widths. In addition, in support elements of this kind, for example their width can also vary over their length, where the cross section of the support element or its width tapers starting from the seat position of the connecting device half. In known wiper blades of this type, DE 19729865.6 A1), the device half engages the support element on its outer longitudinal edges with hook-like projections so that it is affixed to the support element. However, since for the above-mentioned reasons, the maximal width of the support element differs from case to case, for each of these cases, a particular device half, which is adapted to the width of the support element, must be kept on hand, even if the variations in width are relatively slight. This is because the device half must always, even during wiping operation, be connected to the support element so that it does not move lateral to the longitudinal direction of the wiper blade because of the other wiper blade half of the connecting device.
This requirement causes a multitude of device halves to be required since as a rule, each of these halves can be used for only one wiper blade of a single vehicle type.
Comparable problems arise in the two end sections of the support elements, to which cap-like holders must be attached. These caps are intended, for example, to reduce the risk of injury presented by the end edges of the support elements during handling of the wiper blades, for example when replacing them. In known wiper blades of this type (DE 19802451.7 A1), these caps can also aid in the connection between the wiper strip and the support element if they engage the support element, for example with claws, and hold the wiper strip. It is also true of these caps and for their seat positions on the support elements that for the reasons mentioned above, the width of the support elements at their ends varies in size from case to case. Therefore, correspondingly adapted caps must also be produced for each different use, which starting with the manufacturing apparatuses for these caps, down to the storage and the danger of mixing them up during installation, is very cost-intensive.
With the wiper blade according to the invention, by standardizing the width of the support elements in the above-mentioned longitudinal midsection, at least several support element types can be provided with the same device halves so that the manufacturing costs for these halves are reduced and the storage of them is simplified.
Since the wiper blade half of the connecting device embraces the two remote outer longitudinal edges of each support element in a form-fitting manner with longitudinal shoulders, the immobility of the connection between the halves of the connecting device and the support element is further improved.
The multitude of caps can be fundamentally reduced and consequently, the costs for the wiper blade can be considerably reduced.
The above-described features have no influence on the support element design because both in the longitudinal midsection and in the end sections of the support elements, they are continuously stiffened by the add-on pieces positioned there, which already has to be approximately taken into consideration in their dimensioning.
A proper fit of the caps on the support element ends is achieved if the caps embrace the two remote outer longitudinal edges of each of the support element in a form-fitting manner with longitudinal shoulders.
In certain application instances, it is advantageous if the support elements are embodied as one-piece bands, which have the same width in the vicinity of the seat position of the device halves.
With a width of the support elements that exceeds a particular fit measurement in its effective spring regions, it is useful if the width of the seat position is constituted by a partial, lateral constriction of the support element.
However if the support element design falls below the width fit measurement predetermined for the support element, then the width of the seat position can be simply constituted by a partial, lateral widening of the support element.
If the length of the constriction is matched to the length of the wiper blade device half, then an exactly determined seat position for the device half is achieved without having to carry out other measures.
For certain application instances, it is advantageous if the support elements are embodied as one-piece bands, which have the same width in the vicinity of the seat position of the cap.
In order to adapt the fit measurement of the support element width in the vicinity of the seat positions of the caps, the fit measurement can be maintained as a function of the respective width determined by the support element design by virtue of the fact that the width of the seat position for the caps is determined by a partial lateral constriction of the support element or the width of the seat position for the caps is determined by a partial lateral widening of the support element.
The embodiment of the support elements by means of two spring strips, which are disposed parallel to and spaced apart from each other, can in many application instances represent an advantageous alternative to the one-piece support elements.
In this connection, these spring strips that comprise a single support element can be disposed in longitudinal grooves in the wiper strip, which are disposed in a common plane spaced apart from the window and whose bases are spaced apart from each other.
Other advantageous improvements and embodiments of the invention are disclosed in the following description of exemplary embodiments shown in the accompanying drawings.